Microbiology Exam 2 Flashcards
what are bacterial cells capable of
carrying out all necessary life activities
what are the necessary life activities that bacterial cells are capable of
reproduction, metabolism, and nutrient processing
what can bacteria also act as a group
colonies and biofilms
three general shapes of bacteria are
coccus, bacillus, and vibrio
what shape are coccus bacteria
spheres, oval, bean shaped
what shape are bacillus bacteria
cylinder, filamentous, and club shaped
what shape are vibrio bacteria
curved
what shape are paleomorphism bacteria
variations of shapes and sizes
what are mycoplasmas
display extreme variations in shapes
why do mycoplasmas display extreme variations in shapes
due to lack of cell walls
group of cocci that are in pairs
diplococci
group of cocci that are in groups of four
tetrads
what group of cocci show irregular clusters
staphylococci
what group of cocci show chains of few hundreds cells
streptococci
what is occasionally found in short chains
spirilla
what rarely remains attached after cell division
spirochetes
what are the two major groups of appendages
flagella and pili
what do flagella provide
stability
what does pili provide
attachment points of channels
what flagellar arrangement has flagella attached at one or both ends of cells
polar
what flagellar arrangement has a single flagellum
monotrichous
what flagellar arrangement has small bunches or tufts
lophtrichous
what flagellar arrangement as flagella at both poles of the cell
amphitrichous
what flagellar arrangement has flagella dispersed randomly all over surface of the cell
peritrichous
what is the movement in response to chemical signals
chemotaxis
what is positive chemotaxis
movement of the cell in a favorable direction
what is negative chemotaxis
movement of the cell away from a repellant
what is phototaxis
movement towards light
what is it called when cell swims in a smooth linear direction towards stimulus
run
what is it called flagellum reverses the direction causing the cell to stop and change course
tumble
small bristle like fibers sprouting off the surface of certain species of bacteria
fimbriae
pili is used for
conjugation
what is conjugation
partial transfer of DNA from one cell to another
how is production of pili controlled
genetically
what surface coating has thousands of copies of a single protein linked together
s layer
what surface coating provides protection from environmental conditions
s layer
what surface coating is only produced in hostile environments
s layer
what surface coating has repeating polysaccharides that may or may not include protein
glycocalyx
what surface coating from loose around the cell and protects from water loss and nutrients
slime layer
what surface coating is bound more tightly to a cell than the slime layer
capsule
what surface coating is denser and thicker than slime layer
capsule
what is the cell envelope composed of
cell wall, cytoplasmic membrane, outer membrane
a gram positive stain shows
thick walls composed of peptidoglycan and inner cytoplasmic membrane
a gram negative stain shows
outer membrane, thin cell wall, and inner cytoplasmic membrane
characteristics of cell wall
help determine shape of bacteria and provides strong structural support
where is peptidoglycan found typically
cell walls of bacteria
what provides a strong but flexible framework
peptidoglycan